The present invention relates generally to intake manifolds for an internal combustion engine. More particularly, the present invention relates to an improved multi-plenum air distribution manifold with improvements in short runner valve assemblies, manifold tuning valves and shaft quieting mechanisms.
Intake manifolds including short runner valves and manifold tuning valves are known for use in modern fuel injected engines. These systems have provided improvements in performance for today""s engines. Present designs, while generally suitable, still have many areas where improvements in both manufacturing and operation are desirable. Some of the current problems in need of solutions are set forth below.
Because the performance of the engine is directly related to the quickness and efficiency of opening and closing short runner and manifold tuning valves, it is desirable to have the valves operate as friction free as possible. One of the greatest friction areas is along the actuating shafts of the short runner valves. Certainly, using relatively ample clearance in the fittings for these shafts allows low friction operation. However, these clearances also may produce chatter if left unchecked. U.S. Pat. No. 5,992,370 teaches biasing of the shafts for reducing shaft xe2x80x9cchatterxe2x80x9d. Such biasing assemblies are very effective in reducing noise. However, shaft biasing does increase friction, somewhat reducing response time. Therefore, it is desirable to provide a lower friction anti-chatter device.
A second area needing to be addressed is the problem of sticking or binding valve plates. Of course, it is desirable to have valve plates which completely seal off the short runner passages. However, if the plates are not set up properly, they may bind. This is typically due to the thermal expansion of the various parts during warm-up of the engine. There is a need to provide valve plates which prevent binding during thermal expansion of the manifold. Additionally, proper synchronized closure of groups of valves connected on separate shafts is problematic. If for some reason, the plates are not mounted properly, full closure is not realized.
Additionally, there remains a need in the art for providing an improved method for creating an effective sealing arrangement for a manifold tuning valve.
Thus, in accordance with the present invention there is an intake manifold for a vehicle which has improved operational characteristics. The intake manifold includes an intake housing having a plurality of short runner valves for metering air intake. The short runner valves are attached to at least a pair of shafts, opening the valves substantially in unison. A linkage connects the shafts for a synchronized movement therebetween. The linkage includes a lost motion device such that one set of the valves continues to be closed after a valve attached to one of the shafts has reached a closed position. Additionally, a manifold tuning valve configuration is provided which has a radiused surface for engagement of the tuning valve plate and sealing of the manifold chambers. Additionally, an anti-chatter device may be placed in an opening adjacent the shafts holding the short runner valves. The anti-chatter device of the present invention removes any play of the shaft to the bore without imparting biasing on the shaft.
A further understanding of the present invention will be had in view of the description of the drawings and detailed description of the invention, when viewed in conjunction with the subjoined claims.